Hotel television system



HOTEL TELEVISION SYSTEM 6 Sheets-Sheet l Filed June 28, 1949 1 l l l l ll l I l l l I ||1 R E -1 li w mN Q mw. IT mm @JM WOW AMM. n WJ yimy lvmRW L M m m lnld NN N W5 Nw m m N 1/ Q NU l 1 N m www QN \/1\\ NN Q bl S@11M a dw, S ww #Il mj/l 1 f I -L m :N1 iw- 6 Sheets-Sheet 2 ATTO R N EY.|||||ilIJ n W |..u w l. U SUN NQ S w mmm k1 4 www W p wj @wb/W l wm N01N. S Y Y Nm 0 B J m R Q w m d ,S\ S L Oct 9, 1951 w. J. ol-:STREICHERET AL HOTEL TELEVISION SYSTEM Filed June 28, 1949 OC- 9, 1951 W. J.oEsTRElcl-IER ET AL 2,570,475

HOTEL TELEVISION SYSTEM Filed June 28, 1949 6 Sheets-Sheet 5 F/ gn 4 /96BMM@ ATTORNEY Oct 9, 1951 w. J. OESTREICHER ET AL 2,570,475

HOTEL TELEVISION SYSTEM L Filed June 28, 1949 6 Sheets-Sheet 4 ATTORNEYW. J. OESTREICHER ET AL HOTEL TELEVISION SYSTEM Oct. 9, 1951 Filed June28, 1949 N 6 Sheets-Sheet 5 WARREN .OESTREICHER, Sl

SAVA JACOBSON BYZ ATTORNEY INVENTOR DNEY Lloz,

Oct- 9, 1951 w. J. OESTREICHER ET AL 2,570,475

HOTEL TELEVISION SYSTEM Filed June 28, 1949 6 Sheets-Sheet 6 INVENTORWARREN J.OESTREICHER,SIDNEY LIDZ,

SAVA JACOBSON BY/ Ml( ATTORNEY Patented Oct. 9, 1951 UNITED .STATESPATENT OFFICE HOTEL TELEVISION SYSTEM Warren J. Oestreicher, Brooklyn,Sidney Lidz, New York, and Sava Jacobson, Brooklyn, Y.

Application June 28, '1949, Serial'No. 101,762

(Ci. 17e-5.8.)`

8 Claims. l

This invention relates to television installations for hotels,apartments and similar multi-dwelling "structures,

'One of the objects of the invention isa system which permits theinstallation of a certain num- `ber of subscribers with a Vpossibilityof 'adding 'any appropriate number of further subscribers without'substantial change 'in "the system.

Another object of the invention is a system permitting the subscriber toselect one of a predetermined number of stations and to provide a'selection as wide as Vpossible without substantially increasing thecost of installation.

A 'further object ofthe invention is to obtain an optimum of quality foreach program without unduly complicating and increasing cableconnections and cost of equipment.

Still another obj ectof the invention is a central receiver unit whichis compact in structure and yet supple enough to provide any number ofadditional installations without expensive changes in equipment.

A specific object .of the invention is a subreceiver or subscriberreceiver which is rugged in construction so that it may .be used bymanyand diierent people Without losing its high quality reproductioncharacteristics and the .possibility of facile replacement and .repaireven by inexperienced labor.

Another specific object o'f the hinvention is distributing andconnecting means .permitting the wiring of any number of subscriberunits rapidly and without requiring `greater skill as would usually benecessary in setting up electr-ical distributing systems of any othertype.

YThese and other objects .of the invention are illustrated more fully inthe accompanying 4drawings, a description of which follows:

Figure l shows diagrammatically a master receiver station connected overdistribution and connection equipment to a number of subscriberstations.

Figure 2 lshows-certain parts of the master receverand their connectionsto a number of .parallel distributors or separators including a levelcomparing circuit connected between master reoei-ver and distributors.

Figure 3 shows a power supply system for the distributors and .thecomparing circuit.

rFigure 4 shows an automatic .gain .control .system for the masterreceiver.

Figure 5 shows a sub-distributor or a junction box connecting thesubscriber station to the .distribution system.

Figure shows acorresponding circuit diagram.

Figure 7 represents diagrammatically a subr'eceiver or vslave receiveraccording to the invention.

Figure 8 is a circuit diagram `illustrating an important principle ofthe invention embodied in the 'slave receiver of Figure "7.

'nrig'ure 1, l represents fa master receiver -station usually installed'on 'the top oor of the apartment or hotel lstructure to be served'.Station I is shown to'comprisetwo'racks 2 and 3'; rack 2 supports vanumber vof'master receiver units Ail, 5, 6, 1 and l8- each 'having 1aninput circuit connected to an 'antenna 'system 9, lil), H, I2 and I3respectively, and'feach adapted to Lreceive the radio frequency wave vofone television channel. Each 'of the units through `8 Ycontains thecustomary radio frequency amplification, intermediate kfrequencyamplification, I'detector and video amplication stages which are notshown in detail *because they are l'believed to be within the ordinaryskill ofany one familiar with the art of television.

Each'of the master receivers 4 through 8 is also vconnected in 'a mannerto `be explained further 'below but generally'well'known inthe art tocontrol associated monitoring loudspeakers not shown and monitoring`"cathode ray tubes shown at t4, Hi, r6, I1 'and I8, respectively, andso as to permit the station attendants to check and 'control the quality'of picture and sound obtained through the channels served by the masterre- -ceivers The channels and consequently the 'associated antennas vand.master receivers may be selected to any desired number and of anydesired kconstruction without -exceeding the scope rof this .in-

vention.

On their output sides, master receivers V1. through 8 are connected overlines 19, 21], 2|, 422 and .23 to auxiliary amplifiers .24, 25, 2.6, 21Yand .28, respectively, arranged'on rack 3 of .the master sta-tion.

Each master receiver for example, may have on its. output side a -level.of say three volts with an impedance of -say A1.00 ohms. After havingbeen applied over coaxial cables I9 through V23 to amplifiers 211Vthrough -28 the video energy Ymay be required to reach a voltage levelof say 40 volts, with the output .impedance remaining as before at sayohms.

The amplified video output thus obtained in each of ampliers 24 through2B is applied preferably over a number of parallel distributors orseparator stages to coaxial lines 29, 30, 3 I, 32 and 33 respectively,and over a number of sub-distributors or junction or T-boxes connectedin .series .and of .a relatively .great number, say 20, shown at 3ft,35, 36 and 31 respectively, to the subscriber stations or slavereceivers.

As shown in Figure 1, boxes 311 through 31 are connected in series witheach other over coaxial transmission lines 29 through 33 and the coaxialline emerging from. the last of the boxes shown at 31 is fed over line38 into a line termination box 39 or resistance network of say 100 ohms,a device well known per se in the art of transmission line connectionand, therefore, not described in more detail.

Each of boxes 3'4 through 31 serves a subscriber or slave -receivershown 'at 40, 4|, '42, 43, respectively, and provided with cathode rayscreens at 44, 45` 46, 41 and tuners at 48, 49, 50, 5|, re-

tively, through multi-contact connectors 52, 53,

54, 55, respectively. I

In this way it is possible to associate with each set of masterreceivers, 4 through 8, or'with each set of their auxiliary amplifiers,24 through 28,' a great number of subscriber stations arranged in apredetermined order or position in the building.

In the example shown, the subscriber stationsv associated with each ofthe ve parallel groups `oi. five cables derived from the auxiliaryamplifiers, some of which are shown at 39 through 33, are arranged invertical array in the hotel or subscriber groups may be employed withoutexceeding the-scope of the invention.

` 'Figure 2 shows one way to provide proper distribution in accordancewith the principles set forth. Only one of the master receivers is shownand more specically the last stage 16 of video amplier 11. This laststage is a tube of the 6K6 type, the output circuit 18 of which is con-A nected through line 19 to a master monitoring apartment building so asto reduce wiring to a minimum without incurring interference.

Instead of the five lines emerging from each of the amplifiers 24through 28, less or more lines may be derived depending, of course, onthe capacity of the amplier or of the distributors or separatorsassociated therewith, without exceeding the scope of the invention.

In Figure 1, the outputs of auxiliary ampliiiers 24 through 28 are shownto be derived as parallel groups of cables such as 56 through 60, 6|through 65, 66 through 10, 1| through 15, respectively, ij

.say I0 parallel distribution elements with each channel or withauxiliarv amplifier and to regroup them afterwards in ve channel sets,to

kinescope of say 10 inch type which, however, is not shown, suchconnection being well known in the art.

Output circuit 18 is'also connected over coil 80, resistance 8| andcoaxial cable 82 to auxiliary amplier 83; resistor B4 of about 600 ohmsand inductance 85 of I0 microhenries connecting the anode of stage 16 toB+ areused as peaking means.

The inner line of cable 82 is connected over a condenser 96 to controlgrid 81 of a tube 88 of the 6Y6G type. Grid 81 is connected overresist.:- ances 89 and 90 to ground. Part of the grid input. is suppliedover line 9| to a control or level measuring circuit shown in Figure 2at 92. In the embodiment shown, the circuit serves to com pare theheight of the horizontal line level above the D. C. level of the systemas will be explained later on.

The screen grid of tube 88 is connected over resistance 93 to pointl 94of the power supply system diagrammatically shown in Figure 3 anddescribed further below. The output circuit of l tube 88 is connectedover inductance 95 and retake the two channel cables out of theauxiliary amplifier and pass them through a number of distributor unitseach including ve elements,

`the ve elements of these channel units being connected in parallel withnine other units to make up the same number of distribution elei mentsas before.

The manner in which parallel derivation and regroupingr into sets of vecables may be made will be further explained in connection withFigamplifiers 24 through 20 themselves, such division or separationmeans however may also ,be`

set up as separate dividing orseparating stages as will be explainedlater on. The circuit diagram of Figure 2 permits any type orarrangenent without exceeding the scope of the invenion.

As shown in Figure 1 each of the cable bundles 56 through 60, 6| through65, 66 through 10 and 1| through 15, respectively, are grouped intochannel sets of ve and each set is used to feed a number say 20, ofvertically arranged subscribers, some of which are shown at 34 through55.

Alternatively, it is possible without exceeding the scope of thisinvention, to have only cables 24 through 28 emerging from master.receivers 4 through 8 or auxiliary amplifiers 24 through 28 vand tofeed these ve cables only into a number tion, division, grouping orregrouping of the amplifier outputs over a number 0f subscribe$ sistance96 to point 91 of the power supply system of Figure 3. The input side ofinductance is connected over another inductance 93, condenser 99 andresistance |00 to the input grid |0| of a tube |02 of the cathodefollower type which may be also of the 6Y6G type having an anodeconnected to point 94 ofthe power supply system of Figure 3.

The c ontrol grid of tube |02 is connected over resistor |03 to ground.The screen grid of tube |02 is connected over resistor |04 to point |05of the power supply system of Figure 3. The cathode output of tube |02is connected over line |05 in parallel to the input circuits of a numberof separating stages which are likewise of the cathode follower type andpreferably also of the 6Y6G type. These tubes are shown at |01, |08,|09, ||0 and respectively.

Any number of such separation stages may be provided in accordance withthe capacity of the amplifiers, the number of subscriber or subscribergroups, or dependent on any other factors without exceeding the scope ofthe invention.

As already stated above, the distribution or separation stages such asshown at |01 through instead of as shown being assembled to b'erepresentative of or associated with a particular channel, a particularmaster receiver or a particular auxiliary ampliiier, such separationstages may be bundled to berepresentative of or associated withdiiierent television channels, different master receivers or differentauxiliary ampliers.

Alternatively, any type of assembly or association of lines orseparation stages may be provided in accordance with the spacialrequirements of the distribution system or depending on any otherrequirements, without exceeding the scope of the invention.

Separator stages |01 through may be. arranged as already stated beforein the same housingwithauxiliaryamplier 83 or in a sepandere aratehousing such as-shown at |12; andiinfthesame room or in different;rooms, and on: the same iioor or on different floors withoutizexceedeing the scope of the invention.

Housing M2' is shown to comprise five: terminals H3, to |f|f'|.`connecting; the; cathodes oftubes, |01 through l2 to the innerconductors ozfEtranSr mission lines Md through; |22 resnectively In casethe five separator stages |51 through are not as shown connected in'.paralleli to one auxiliary amplier'cr channel but each. of the stages|51 through to; different ample fiers or; channels, then points: |23throughV |:2-1; and: |25: throughV |32 will. eachY have to' beprovidedwith coaxial linev terminals toypermtzcon: tinuous wiring in paralleltoothergfiveestagevsets of separators.

Cable |05. would be connected; to the contrai grid of one of the stages|01 throught llzlil'; forexample, at pointA |28 tothe control7 grid:cfr-stage. llls.

The remaining stages |08 throughY would be connected in thefollowing'manner.:

Point |28 would be connectedtov the: gridY of stage; m8. at point |24.Control gridfof, stage; |58 would he connected to control grid. offstage|15. at point |25. Control grid; of. stage H- would be. connected tocontrol grid' of stage |-|El-ait;p.oint |26` and control grid of stage|v| |15 would' be connected to control grid oiV stage, at point |21.

Thus, in the particularmode of. distribution shown in Figures 1 and 2,line |56 would beacon.- nected effectively in parallel to` allthecontrol grids of the associatedseparationtages and'distortionlessseparation over a:numberfofgdistributioncables l I3 through|22fwouldzbe-e1ected in an extremely simple mannen withY a minimum ofcircuit connections and. mutual interference;

Each separation stage has an. input circuit independently controllableandi consisting. as shown in the example of stage |;|11-ofpotentiorneter |33, the end terminal of which; is con: nected over aresistance |343 toground andthe center tap of which is connected; over;`condenser |35 and resistor. I 55 to the control. grid |31 of stage |51.The start winding of potentiometer |33 is shunted by capacity |38.

The junction` point of condenserA |35? andresistor |35 is connectedoverresistorc |35 to ground. The cathode of. each separator stage isalso connected as shown in stage |11-, over resistor |45 to ground andover resistor |4| to point |42 of control circuit 92. The correspondingpoints |43 through |465 in stages |58 through are connected tocorresponding points |43 through |45 in circuit a2. These points formthe terminals of a switch. |41y the function of which will be explainedfurther below.

The cathode of each separator stage is fur.- ther connected over twocondensers |48; Mcon;- nected in parallel to the inner conductorv oftransmission lines ||6 through |22. Points |42 through |45 are alsoconnected over condenser |55 to ground. The outer conductors of trans'-mission lines ||3 through |22 are grounded.

The screen grid of each separation stage, is connected, as shown forexample in stage |01, over resistance |5| to point |55 of the powersupply circuit shown in Figure 4. The; anode of each stage is connected,as shown for example in stage lul, to point 94 of the power supplycircuit of 1figure 3. The heater lament of each element is shown to beconnected, as forl example in stage |51, to point |52 of power supplyvcircuit vof Figure 3.

' Circuit: 942.5. as; alre-ady'statedA above,- Y representsdiagrammatically a comparison circuit to evalu ate; the.` height: offthe horizontalline4 abovez the De, Cl. level? of; each: vertical:distributing: system or riser-5i" Eachof: the; risers` is connected-'fyfor measurement by; switching; arm; |41-tog one of the terminalipositions |42 through |45l This@ will conneataone off.` theseterminalsover capacityy |53; to grid-: |54: of,l twin triade |55; thesecondi grid |56. of" twins triode |55.- is connectedi asv alreadystated: above, over line 9| to the junction point of;resistancesniSand'; 95". Grid |54 is` alsoxcon.- nected dvergresistance"|51 to ground. Point |46! efswitch |41 f is connected overcondenser|58-V to. tlieancd'e- |55` associated withl grid; |56; while` anode |60associated with grid |54 is connected to theprimary of, a; transformer|6| the, secondary of which feeds over rectifier |62, poten: tiometer|63i to a' measuring instrument Ild, shunted by: condenser |55; Anode|595 is con:- nected: over resistance |56.' to, point 9 4: ofthe powersupply circuitof Figurev 3. Similarly, the remaining: terminal' of.:`the primary of transformer. |6| is-g alsoyccnnejcted to point 94. 'Thecathode associated with grid |54' is connected over; aicapacity'resistance combination |511; |68 tdigroundiwhileythe cathodeassociated: with grid |53. is grdunded. over resistance` |69.

'I'.hefpower supplycircuit ofEigureB comprises input plug |10 forconnectingthe circuit.toV a 1:10.x volt-60, cycle alternating currentline. '|1| representsya ampere fuse, |52; a signal-lamp; |13 isafsmoothingffcondenser of .25.micromicrofarad forVV 600 volts;There-areftwo'transformers or transformer sections |r14;. H5,respectively; one supplies high voltage oven a. twin. rectifier bridge;`circuit#` |165. the output-i off which; is con:- nectedrover a lterchoke@` |11 to point 94. The terminals of choke' |151 are; also;connected; O ver condensersw' |18 |15: of, 60G-and' 400 microfaradsrespectively; to ground.

The; l'cwfvoltagef transformer or transformer section |15= is; connectedat its primary over a secondV transformer or.VIV transformer section|89; resistory |=|;.re.otier |82, choke |83'and resistor v|54 toterminal; |155.. The secondary of; trans',- former |851 is shunted by.a. 50 microfarad` con'.- denser |85 while the terminals of resistor.v|84 are connected fover -40 microfarad condensers 86, |31',respectively, to ground. The'junctionpoint of choke |33 and resistor |84is connected to point 5820i the` separator system of Figureiz.

Figure 4 shows an-automaticgain control systemY for the purpose of theinvention. There again'one'of the master receiversv is shown at |88,A|89 represents an antenna, |88 a tuner, |90- a filter having acharacteristic such asshown inside of'boxV |90. Filter |9631 serves toreduce sound rejection. In this way itis possible to tap, as itisV shownat I 91, a portion ofthe sound coming from tuner |88 and to pass it overintermediate.. frequency soundamplfier |92', limiter |93; discriminator|94', audio amplier |95 to loudspeaker |96; Another, portion of thesound energy-passing tuner |83 isapplied to video amplier |91, a stageof which is shown at. |98,v |58 represents-a` radiofrequency stagepreferably the last-one, in the-radio frequency amplifier of the masterreceiver; |98, for example may be a 6,16 twintype-V tube. Its outputterminals are interconnectedatipoint |39 over. resistances 280, andconnected over resistance 20| to the inner conducten Qf;.'a transmissionline` 202 theY outer congrounded over a 1500 micromicrofarad'condenser203.

The inner conductor of transmission line 20| is connected over aresistance 204 of 2'1 kiloohms to the anode of an automatic gain controlamplifier 205 which also acts as a noise clipper. The input electrode ofstage '205 is controlled over a resistor 206 of 460 kiloohms and aresistor 201 of 100 kiloohms from the output circuit of va dioderectifier 208 the cathode of which is connected over a resistance 209 of82 kiloohms shunted by capacity 2|0 of .001 microfarad and a'seriesresistor 2|| of 10 kiloohms to the anode and input circuit of rectifierdiode 208. The junction point of parts 209, 2|0 is connected to -100volt.

Stage 205 in order to act as a noise clipper is of the 6AT6 type andprovided with two anodes shown at 2| 2, 2 I 3 respectively, which areshunted by resistor 201. Thus only the synchronizing signals arepermitted to pass while noise signals will be clipped off. The cathodeof stage 205 is connected over a condenser 2|4 of .25 microfarad to thecontrol grid and also to the variable tap of a potentiometer 2|5 of lkiloohm. One of the fixed terminals of potentiometer 2|5 is connectedover resistor 2 6 of 22 kiloohms to ground; the other fixed terminal ofpotentiometer 2|5 is connected over another resistor 2|1 of 330 kiloohmsto -100 volt.

As already stated above the output anodes of the combined gain controland noise clipper stage 205 is connected over transmission line 202 tothe output circuit of radio frequency stage |98. I-Iowever, the sameoutput anode is also connected over a resistance-capacity combination2|8, 2|9 of 220 kiloohms and .25 microfarad, respectively, to a diode220 of the 6AL5 type connected to operate as a gain control limiter.

In order to achieve this purpose the junction point of parts 2|8, '2I9is connected to the cathode of diode 220 while the anode thereof isconnected over a 270 kiloohm resistor 22| to -18 volt and over a 47kiloohm resistor 222 to ground. Thus, it is assured that onlysynchronizing pulses of predetermined level are passed through theautomatic gain amplifier 205. The control pulses of stage 205 are passedfrom output -circuit 2|8, 2|9 over line 223 to the input circuit of theamplier stages which are to be controlled automatically.

In the particular case automatic gain control is applied to the biasingcircuits of the intermediate frequency amplifier stages shownschematically at 224, 2'25, 226, 221. The first intermediate frequencyamplifier stage 224 has an input grid connected at 228 to the converter(not shown), and the last intermediate. frequency stage 221 has anoutput circuit connected over a 210 microfarad capacity 229 and aseconddetector 230 and point 23| to the video output amplier (not shown).Condenser 229 is also connected over another condenser 232 of 33microfarads to the input circuit of automatic gain control rectifier'208 which may be of the 6AL5 type.

Potentiometer 2I5 is connected to operate as contrast control.

The anode of stage 221 is also connected over a 5,600 ohm resistor 233and a 1500 microfarad condenser 234 to ground and also over a 1 kiloohmresistor 234 to 135 volt. The cathode of detector 230 is connected overan adjustable choke 236 to ground.

' In this way with a minimum of circuit elements an extremely eflicientgain control will 'be obtained even at the occurrence of relativelylarge changes due to widely varying load conditions prevailing in hotelor apartment television distribution systems.

Figure 5 shows the mechanical lay-out of a junction box embodyingcertain features of the invention.

Figure 6 shows a corresponding circuit diagram.

In Figure 6 the five incoming coaxial cables schematically indicated at231 through 24| are connected with their inner conductors, overresistors 242 to 246 of 1800 ohms each to the inner conductors ofanother set of coaxial cables schematically shown at 241 to 25|respectively. The outer conductors of cables 231 through 24| aregrounded. The inner conductors of cables 241 through '25| lead toterminals 252 through 256 of a multi-contact socket. Terminals 252through 256 are also grounded over a set of resistors 251 through 26| of100 ohms each. A terminal plug indicated schematically in dotted linesat 262 ts into a corresponding socket of the slave receiver (not shown)to permit connection of the different coaxial cables with the differenttransmission channel circuits of the slave receiver.

The coaxial cables 234 through 239, as shown at points 26| through 265,are continued to the next junction box.

The cables are all low-loss cables each capable of carrying a frequencyrange of about 4.5 mega.- cycles.

The invention is not limited to the impedance relations shown althoughthese relations are preferred examples of the invention.

The cables are armored but it is also possible to use a polyethylenetubing provided with aluminum plating. This will increase flexibility ofthe cables and facilitate distribution of a greater number of channels.

Printed circuits may also be used especially in the separator andjunction units, without exceeding the scope of the invention.

The ve cables representing a five-channel transmission line to the slavereceivers are intertwined so as to reduce distortion to a minimum andalso to permit utmost flexibility and easy access to all types oflocalities and any number of subscribers.

In Figure 5, 266 represents the junction box diagrammatically indicatedin Figure 6. Two five-line cables 261, 268 represent the continuingtransmission line entering and leaving box 269 through holes 210, 21| inthe front panel 212 of box 269. Front panel 212 also carries, underneaththereof, a five-compartment structure 213 through 211 which at itsendshas anges 218, 219 provided with holes 280 for connecting frontpanel 212 which preferably is of metal to the cover portion 28| whichmay also be of metal or of metallized plastic. Each of the compartments213 through 211 has two opposite openings 282, 283 permitting entranceof cables 264, 265, in such a way that the armored or outer portion issoldered around the entrance of openings 282, 283 while the innerinsulation .or core portion of cables 264, 265 shown at 286, 281 enterscompartments 213 through 211. The conductors 288, 289 are soldered toopposite sides of terminals 290 attached to terminal plates 29| which inturn are insulatingly attached to the separation walls 292 ofcompartments 213 through 211. The five upper and lower terminals 290 and293 are interconnected through resistances 294v of 1800 ohms each andthe lower terminals are connected over barium sulfate, and 64.83 percent water. The results were as indicated in the following table:

To test the resistance of my drilling muds to sodium chloridecontamination, tests were run using a base mud to which had been addedat least 50,000 parts per million of sodium chloride. The base mudcomprised 0.8 per cent bentonite, 18.0 per cent kaolin, 8.0 per centE'zmix, 0.17 per cent calcium sulfate, 26.20 per cent barium sulfate,and 64.83 per cent water, the sodium chloride being added to the Waterphase. The results of this test were as shown in the following table.

Table 3 Stormer Gel Strength API Additive, lscg (g') water Mud, 1b./bb1.Rit M Loss, pH

cps. Initial 10 min. m1'

l 1i 15 15 si 7.9 o 12 15 i7 e4 7.9 1 5 a 5 t5 7. 9 2 9 o 30 52 7.9 4 5o o 25 7. 9 c 7 o o 6.8 8.o

l This was a sample of base mud before the addition of sodium chloride.

The above simple experiments are merely representative and are given toshow how water soluble ethyl sulfoethyl cellulose may be used in waterbase drilling muds by those skilled in the art and are not to beconsidered as unduly limiting my invention.

It is to be understood that While a theory of operation has beenadvanced, it is not the only or necessary one, but has only beenadvanced to facilitate the disclosure and this invention is not limitedto any theory of operation or action. It is to be understood that theinvention is not to be limited to the specific details described. Forexample, the tests with treating and control agents indicate that watersoluble ethyl sulfoethyl celluloses are somewhat inert chemically andthat all the treating and control agents of the well drilling fluid andwell controlling uid arts may, after a simple test for solubility andlack of obvious adverse reaction, be employed without invention in mywater soluble ethyl sulfoethyl cellulose drilling and controllingfluids. My invention is, therefore, defined by the following claims.

Having described my invention, I claim:

l. A water base well drilling mud comprising, in combination, suicientwater to maintainthe mud as a fluid, suiiicient clayey material to forma filter cake on the Wall of the well, and a water soluble ethylsulfoethyl cellulose selected from the group consisting of ethylsulfoethyl cellulose and the Water soluble salts thereof in an amountsuflicient to reduce the water loss due to filtration through saidfilter cake without increasing 6 the viscosity of said weil drilling mudto such an extent that it cannot be circulated.

2. A water base well drilling mud comprising, in combination, suicientwater to maintain the mud as a iiuid, sufficient clayey material to forma filter cake on the wall of the well, and a water soluble ethyl sodiumsulfoethyl cellulose in an amount suflicient to reduce the water lossdue to filtration through said lter cake without increasing theviscosity of said well drilling mud to such an extent that it cannot becirculated.

3. A water base well drilling mud comprising, in combination, sufficientwater to maintain the mud as a fiuid, sufficient clayey material to forma filter cake on the wall of the well, and a water soluble ethylammonium sulfoethyl cellulose in an amount suicient to reduce the waterloss due to filtration through said filter cake without increasing theviscosity of said well drilling mud to such an extent that it cannot becirculated.

4. A water base well drilling mud comprising, in combination, sufficientwater to maintain the mud as a fluid, sumcient clayey material to form alter cake on the wall of the well, and a water soluble ethyl magnesiumsulfoethyl cellulose in an amount sufficient to reduce the water lossdue to filtration through said filter cake without increasing theviscosity of said well drilling mud to such an extent that it cannot becirculated.

5. A water base Well drilling mud comprising an aqueous uid mixturecontaining suspended inorganic solids which form a filter cake on thewall of the well and a water soluble ethyl sulfoethyl cellulose selectedfrom the group consisting of ethyl sulfoethyl cellulose and the watersoluble inorganic salts thereof in an amount suicient to reduce thewater loss due to filtration through said filter cake without increasingthe viscosity of said well drilling fluid to such an extent that itcannot be circulated.

6. A water base well drilling mud comprising an aqueous fluid mixturecontaining suspended inorganic solids which form a filter cake on thewall of the well and a water soluble ethyl sodium sulfoethyl cellulosein an amount sufficient to reduce the water loss due to filtrationthrough said filter cake without increasing the viscosity of said welldrilling mud to such an extent that it cannot be circulated.

7. A water base well drilling mud comprising an aqueous fluid mixturecontaining suspended inorganic solids which form a lter cake on the wallof the well and a water soluble ethyl ammonium sulfoethyl cellulose inan amount suliicient to reduce the water loss due to filtration throughsaid filter cake without increasing the viscosity of said well drillingmud to such an extent that it cannot be circulated.

8. A water base Well drilling mud comprising an aqueous fluid mixturecontaining suspended inorganic solids which form a filter cake on thewall of the well and a water soluble ethyl magnesium sulfoethylcellulose in an amount sufficient to reduce the water loss due tofiltration through said filter cake without increasing the viscosity ofsaid well drilling mud to such an extent that it cannot be circulated.

9. A water base well drilling mud comprisingy in combination, sufficientwater to maintain the mud as a fluid, sucient clayey material to form afilter cake on the wall of the well, and a water soluble ethylsulfoethyl cellulose compound selected from the group consisting ofethyl sulfoethyl cellulose, ethyl alkali metal sulfoethyl cellulose,ethyl alkaline earth metal sulfoethyl cel- 7Y lulose, andv ethylammonium sulfoethyl cellulose in an amount suicient to reduce the waterloss due to filtration through said lter cake without increasing theviscosity of said well drilling mud to such an extent that it cannot becirculated.

10. A waterbase well drilling mud comprising, in combination, sufcientwater to maintain the mud as a iluid, sufficient clayey material to forma filter cake on the wall of the well, and a water soluble -ethyl alkalimetal sulfoethyl cellulose in an amount sufficient to reduce the waterloss due to-ltration through said lter cake without increasing theviscosity of said well drilling mud to such an extent that it cannot becirculated.

11. A water base well drilling mud comprising, in combination,sufficient water to maintain the mud as a fluid, suiiicient clayeymaterial to form a filter cake on the wall of the well, and a watersoluble ethyl alkalineY earth metal sulfoethyl cellulose in an amountsuiiicient to reduce the water loss due to filtration through said ltercake without increasing the viscosity of said well drilling mud to suchan extent that it cannot be circulated. Y

12. A water basev well drilling mud comprising, in combination,suflicient water to maintain the mud as a iluid, sufficient clayeymaterial to form a filter cake on the wall of the well, and a watersoluble ethyl potassium sulfoethyl cellulose in an amount sufficient toreduce the water loss due to filtration through said lter cake withoutincreasing the viscosity of said well drilling mud Lo such an extentthat it cannot be circulated.

' 13. A water .basev well drilling mud comprising, in combination,suilcient'water to maintain the mud as a fluid, sullcient clayeymaterial to form aklier cake on the wall of the Well, and a watersoluble ethyl lithium sulfoethyl cellulose in an amount suicient toreduce the water loss due to filtration through said filter cake withoutincreasing the viscosity of saidwell drilling mud to such an extent thatit cannot be circulated.

14. A process for forming a lter cake, having a low rate of ltration offluid therethrough, on

the wall of a well'by the deposition of colloidal clayey solids from awater-base drilling mud cir-l culated along said wall which comprisesadmixing with said drilling mud and interacting therewith a watersoluble ethyl sulfoelhyl cellulose selected from the lgroup consistingof ethyl sulfoethyl cellulose and the water soluble inorganic saltsthereof in an amount sufficient to decrease the rate of ltration offluid through said filter cake but insufficient to increase theviscosity of said drilling mud to such an extent' as to render ituncirculatable and then forming said filter cake from the resultingdrilling mud.

15. A processv for forming a lter cake, having a low rate of ltration offluid therethrough, on the wall of a well'by the deposition ofYcolloidal clayey solids from a water base drilling mud circulated alongsaidl wall which comprises admixing with said drilling` mudand`interacting therewith a water solubleethylalka-li metal sulfoethylcellulose in an amountsufficient tcdecrease the rate of filtration of'iluid through saidfilterfcake but insufficient to increase theviscosity of said drilling mud to such an extent as to render ituncirculatable and then forming said filter cake from the resultingdrilling mud.

16. A process for forming a iilter cake, having a low rate of ltrationof'iiuidV therethrough, on the wall of a well by thedeposition ofcolloidal clayey solids from a water base drilling mud'circulated alongsaid wall which comprises admix- 8 ing with said drilling mud 'andinteracting therewith a water soluble ethyl alkaline earth metalsulfoethyl cellulose in an amount suiiicient to decrease the rate ofltration of fluid through said filter cake but insufcient to increasethe viscosity of said drilling mud to such an extent as to render ituncirculatable and then forming said filter cake` from the resultingdrilling mud.

17. A process for forming a filter cake, having a low rate of filtrationof fluid therethrough, on the wall of a well by the deposition ofcolloidal clayey solids from a water base drilling mud circulated alongsaid wall which comprises admixing wih said drilling mud and interactingtherewith a water souble ethyl sodium sulfoethyl cellulose in an amountsucient to decrease the rate of filtration of fluid through said filtercake but insufcient to increase the viscosity of said drilling mud tosuch an extent as to render it uncirculatable andA then forming saidfilter cake from the resulting drilling mud.

18. A process for forming a filter cake, having a low rate of ltrationof iiuid therethrough, on the wall of a well by the deposition ofcolloidal clayey solids from a water base drilling mud circulated alongsaid wall which comprises admixing with said drilling mud andinteracting therewith a water soluble ethyl ammonium sulfoethylcellulose in an amount suflicient to decrease the rategof filtrationv offluid through said lter cake but insufficient to increase the viscosityof said drilling mud to such an extent as to render it uncirculatableand then forming said lter cake from the resulting drilling mud.

19; A process for forming a filter cake, having a low rate of ltrationof fluid therethrough, on

the wall of a well by the deposition of colloidaly n drillingmud .tosuch an extent as to ,render vit uncirculatable and then forming saidfilter cake.

from the resulting drilling mud.

20. The drilling mud composition of claim v 5 wherein said ethylsulfoethyl cellulose compound cellulose.`

2l. The drilling mud composition of claim 5 wherein said ethylsulfoethyl cellulose compound is vawatcr soluble ethyl alkaline earthmetal sul.-

foethyl cellulose.

122. rThe drilling mud composition of claim 5 wherein said ethylsulfoethyl cellulose compoundA is `a water-soluble ethyl potassiumsulfoethyl cellulose` 23. The -drilling mud composition of claim 5wherein said ethyl sulloethyl cellulose compound is a water solubleethyl lithium sulfoethyl cellulose.

v"24; A process for forminga lter cake, havinga low rate of filtrationof lfluid therethrough, on the wall of. a 'well by the depositionofinor-v ganicsolicls from a water base drilling mud circulated alongsaid .wall which comprises admixing with said drilling mud andinteracting.therewii'ihV alzwater soluble ethyl sulfoethylcellulose-selectedfrom the group consisting of ethyl sulfoethylcellulose and the-water soluble inorganic salts there.

of in an amount suliicient to decrease the rate of filtration of iluidthrough-said lter cakeI butv insufcient to. increase the viscosity ofsaid drill'

